A pair of American B-52H bombers was escorted by two Japanese F-2 fighter aircraft and two South Korean KF-16 fighter jets during a trilateral flight on Friday.

It was reported last week that North Korea plans to triple the number of troops fighting with Russia along the front lines in Ukraine—sending an additional 25,000-30,000 troops. Troops will arrive in the next few months, adding to the 11,000 North Korean troops that were sent in November.

North Korea is now supplying as much as 40% of Russia’s ammunition for the war in Ukraine as the partnership between Pyongyang and Moscow deepens, according to the head of Ukrainian military intelligence.